Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea.
LG Chem., LG Science park E6 Block, 30 Magokjungang 10-ro, Gangseo-gu, Seoul, 07796, Republic of Korea.
Nat Commun. 2019 Jan 14;10(1):188. doi: 10.1038/s41467-018-07975-4.
Uncontrolled growth of insulating lithium sulfide leads to passivation of sulfur cathodes, which limits high sulfur utilization in lithium-sulfur batteries. Sulfur utilization can be augmented in electrolytes based on solvents with high Gutmann Donor Number; however, violent lithium metal corrosion is a drawback. Here we report that particulate lithium sulfide growth can be achieved using a salt anion with a high donor number, such as bromide or triflate. The use of bromide leads to ~95 % sulfur utilization by suppressing electrode passivation. More importantly, the electrolytes with high-donor-number salt anions are notably compatible with lithium metal electrodes. The approach enables a high sulfur-loaded cell with areal capacity higher than 4 mA h cm and high sulfur utilization ( > 90 %). This work offers a simple but practical strategy to modulate lithium sulfide growth, while conserving stability for high-performance lithium-sulfur batteries.
绝缘的硫化锂的不受控制的生长导致硫阴极的钝化，这限制了锂硫电池中高硫的利用率。在基于具有高古特曼给体数的溶剂的电解质中可以增加硫的利用率；然而，剧烈的锂金属腐蚀是一个缺点。在这里，我们报告说，使用具有高给体数的盐阴离子，如溴化物或三氟甲磺酸根，可以实现颗粒状硫化锂的生长。使用溴化物通过抑制电极钝化来实现约 95%的硫利用率。更重要的是，高给体数盐阴离子的电解质与锂金属电极明显兼容。该方法实现了具有高于 4 mA h cm 的面容量和高硫利用率（>90%）的高载硫电池。这项工作提供了一种简单但实用的策略来调节硫化锂的生长，同时保持高性能锂硫电池的稳定性。
